With that little information, it's very hard to give a useful answer.

The things that will determine the answer are whether you need referential integrity between the systems, whether...

Please note: 10 year old post, and your definition of recovery is incorrect. What you describe is a restore.

Could you post the queries and execution plans, the ones using the most CPU only.

From multiple previous experiences upgrading, it'll be a small number of queries that have degraded in performance. Identify them, and either rewrite or use a hint to get them to...

Yup, not repairable, and with no backups you're pretty limited in what you can do.

Try exporting the damaged tables in chunks, filter on the clustered index key. This...

If there's millions of rows in a table variable, that's likely a problem. Try a temp table instead.

There's two possible things that come to mind.

1) A backup log with norecovery
2) A backup log with no_truncate

1st if I need to leave the DB...

And how many times does something have to happen before it is 'pervasive'? I'm done, I'm not...

And forum ate my reply somehow, so you get the less diplomatic version.

I don't normally bite. It's not my job to do your research. (and besides, my doing so is unlikely to change your mind)
https://meta.stackoverflow.com/questions/309908/diminishing-numbers-of-women-in-programming-and-the-so-experience
https://meta.stackexchange.com/questions/30411/what-can-stack-overflow-do-to-persuade-female-programmers-to-participate-more
https://meta.stackoverflow.com/questions/281295/does-the-so-community-view-itself-as-gender-neutral/281304#281304

But...

Something like this would work better for multiple row updates. It's still not ideal, as you don't know when the change was made, and it will only work if the...